std::toupper
Defined in header <cctype> | ||
int toupper(int ch ); | ||
Converts the given character to uppercase according to the character conversion rules defined by the currently installed C locale.
In the default "C" locale, the following lowercase letters abcdefghijklmnopqrstuvwxyz are replaced with respective uppercase letters ABCDEFGHIJKLMNOPQRSTUVWXYZ.
Contents |
[edit]Parameters
| ch | - | character to be converted. If the value of ch is not representable as unsignedchar and does not equal EOF, the behavior is undefined. |
[edit]Return value
Converted character or ch if no uppercase version is defined by the current C locale.
[edit]Notes
Like all other functions from <cctype>, the behavior of std::toupper is undefined if the argument's value is neither representable as unsignedchar nor equal to EOF. To use these functions safely with plain chars (or signedchars), the argument should first be converted to unsignedchar:
char my_toupper(char ch){returnstatic_cast<char>(std::toupper(static_cast<unsignedchar>(ch)));}
Similarly, they should not be directly used with standard algorithms when the iterator's value type is char or signedchar. Instead, convert the value to unsignedchar first:
std::string str_toupper(std::string s){std::transform(s.begin(), s.end(), s.begin(), // static_cast<int(*)(int)>(std::toupper) // wrong// [](int c){ return std::toupper(c); } // wrong// [](char c){ return std::toupper(c); } // wrong[](unsignedchar c){return std::toupper(c);}// correct);return s;}
[edit]Example
#include <cctype>#include <climits>#include <clocale>#include <iostream>#include <ranges> int main(){for(auto bd{0};unsignedchar lc : std::views::iota(0, UCHAR_MAX))if(unsignedchar uc = std::toupper(lc); uc != lc)std::cout<< lc << uc <<(13==++bd ?'\n':' ');std::cout<<"\n\n"; unsignedchar c ='\xb8';// the character ž in ISO-8859-15// but ¸ (cedilla) in ISO-8859-1 std::setlocale(LC_ALL, "en_US.iso88591");std::cout<<std::hex<<std::showbase;std::cout<<"in iso8859-1, toupper('0xb8') gives "<< std::toupper(c)<<'\n';std::setlocale(LC_ALL, "en_US.iso885915");std::cout<<"in iso8859-15, toupper('0xb8') gives "<< std::toupper(c)<<'\n';}
Output:
aA bB cC dD eE fF gG hH iI jJ kK lL mM nN oO pP qQ rR sS tT uU vV wW xX yY zZ in iso8859-1, toupper('0xb8') gives 0xb8 in iso8859-15, toupper('0xb8') gives 0xb4[edit]See also
| converts a character to lowercase (function) | |
| converts a character to uppercase using the ctype facet of a locale (function template) | |
| converts a wide character to uppercase (function) | |
C documentation for toupper | |
[edit]External links
| 1. | ISO/IEC 8859-1. From Wikipedia. |
| 2. | ISO/IEC 8859-15. From Wikipedia. |
